Inlet distributor for storage tanks

ABSTRACT

A small distributor tank with perforated top is provided for installation on the floor of a larger storage tank, whereby petroleum products to be stored can be introduced through an inlet line to the distributor tank without agitating sediment on the bottom of the storage tank, and with a minimum of splashing friction which in conventional tank-filling devices tends to generate static electricity. Optional flow-directing baffles may also be included within the distributor tank.

United States Patent Burch et al.

[54] INLET DISTRIBUTOR FOR STORAGE TANKS [72] Inventors: Charles 0.Burch, 645 S. Walnut Ave., Arlington Heights, 111. 60005; David H. May,1336 Central Ave., Wilmette, 111. 60091 221 Filed: Nov. 3, 1969 211Appl.No.: 873,551

[52] [1.5. CI ..l37/576, 137/592 [51] Int. Cl. ..B65d 25/04, 867d 5/04[58] Field oi Search ..l37/592, 264,590, 576

[56] References Cited UNITED STATES PATENTS 675,677 6/1901 Sanford..l37/592 X 2,689,905 9/1954 Harris ..l37/576 X 2,719,583 10/1955 Malick..l37/576 X Feb. 1, 1972 2,749,939 6/1956 Bray 1 37/592 2,767,73610/1956 Lackinger ..l37/590 X FOREIGN PATENTS OR APPLICATIONS 1,205,2954/1959 France ..137/592 Primary Examiner-William R. ClineAttorney-Milton W. Lee, Richard C. Hartman, Lannas S. Henderson, DeanSandford and Robert E. Strauss [57] ABSTRACT A small distributor tankwith perforated top is provided for installation on the floor of alarger storage tank, whereby petroleum products to be stored can beintroduced through an inlet line to the distributor tank withoutagitating sediment on the bottom of the storage tank, and with a minimumof splashing friction which in conventional tank-filling devices tendsto generate static electricity. Optional flow-directing baffles may alsobe included within the distributor tank.

8 Claims, 4 Drawing Figures PATENTEIJ FEB m2 3,53

INVENTORS f7; 4 0942455 0. EURCH XL 5W INLET DISTRIBUTOR FOR STORAGETANKS BACKGROUND AND SUMMARY OF INVENTION In conventional storage tanksfor petroleum products the inlet line generally terminates near thebottom of the tank. Oil flowing into the tank causes eddies and currentswhich tend to agitate foreign materials settled on the bottom of thetank such as dirt, water, iron oxide, silica, insoluble hydrocarbonproducts, etc., which are usually present in small quantities inpetroleum distillates. Conventional outlet lines from such storage tanksare normally arranged so that little or no sediment on .the bottom ofthe tank is picked up in the outgoing oil stream. Sometimes, the mouthof the outlet line is located a substantial distance above the floor ofthe tank to minimize sediment pickup.

However this is not completely efiective where sediment is agitated andmixed with the oil in storage by the conventional flow of incoming oilas described. As a result it has been necessary in the past to resort toperiodic tank cleaning, resulting in decreased total tank utilizationand supply problems resulting from tankage being out of service. Also,in some tank outlet systems filters are utilized, and the presence ofsubstantial foreign material in the withdrawn oil necessitates frequentchanging of filter cartridges. A principal objective of the presentinvention is to provide an inlet distributor which will avoid anysubstantial agitation of sediment on the bottom of the tank, therebypermitting withdrawal of a cleaner product stream with less frequenttank cleaning and increased total tank utilization. Also, the life offilter cartridges in the outlet system is greatly increased, and in somecases it may be feasible to discontinue the use of filter units.

The conventional tank-filling systems described above are also prone tocreate a fire hazard during the initial fill cycle of an empty tank.Even though the inlet line to the tank discharges incoming fluid only afew inches above the floor of the tank, there is a considerable periodof sloshing and splashing before the liquid level in the tank is highenough to submerge the mouth of the inlet line. During this period, thefriction of the splashing liquid may generate sufficient staticelectricity to bring about a static discharge which, if the air/fuelratio in the tank vapor space permits, may cause an explosion. Thisparticular hazard is most often encountered in the storage of lightpetroleum distillates such as kerosene or jet fuel. It is anotherprincipal object of the invention to reduce to a minimum the splashingof liquid during the filling of storage tanks, thereby substantiallyeliminating the explosion hazard normally associated with conventionalfilling systems.

The foregoing and other objects are achieved herein by the use of arelatively small inlet distributor tank which is positioned on the floorof a conventional storage tank, preferably near an outer wall thereof,and into which the liquid inlet line discharges downwardly and laterallyonto the floor thereof. The distributor tank is preferably cylindricalin shape, comprising substantially continuous enclosing sidewalls, andhaving a multiperforate, disc-shaped cover plate. The size of thedistributor tank is such that the discharge end of the liquid inlet linebecomes almost immediately submerged in oil, thus eliminating anysplashing of liquid and resultant static electricity hazard. The liquidinlet line is positioned so as to impinge incoming liquid on the floorand/or sidewalls of the distributor tank, whence the flow is broken upand redistributed in such fashion that there is a continuous, gentleupward flow of incoming liquid through the multiperforate cover plate ofthe distributor tank. In order to assist in breaking up the force of theliquid flow discharging from the inlet line, one or more flow-directingbafiles may be provided in the distributor tank, positioned so as toredirect portions of the incoming fluid against a wider area of thesidewalls of the distributor tank, thereby further minimizing any dangerof strong liquid currents overflowing the distributor tank anddisturbing sediment on the bottom of the storage tank. Details of theapparatus and its operations will be more apparent from the descriptionwhich follows.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a vertical sectional view of aconventional storage tank, illustrating a preferred position therein ofthe distributor tank.

FIG. 2 is a plan view of the storage tank and distributor tank of FIG.I, further illustrating the relative positions of the two.

FIG. 3 is a detailed plan view, partly in section, of the distributortank and inlet line shown in FIG. 1.

FIG. 4 is a vertical cross-sectional view of the distributor tank andinlet line taken along line 4-4 of FIG. 3.

DETAILED DESCRIPTION Referring now to the drawings, FIGS. 1 and 2illustrate a desirable relative positioning of the distributor tank 2 onthe floor of conventional storage tank 4. Storage tank 4 may be of anydesired size, and the size of the distributor tank is adjusted inrelation to the size of the inlet line and the expected velocity ofproduct in this line. Normally the diameter of the distributor tank isabout one-tenth to one-twentieth that of the storage tank, preferablyabout one-fifteenth. The height of the distributor tank will depend tosome extend upon its diameter, but mainly upon the volume rate at whichfluid is to be delivered via inlet line 6. Large flow rates willnormally require a somewhat greater tank height in order to obtain aneven upward flow of liquid through the top thereof. In general, it maybe said that the distributor tank height should be about two to sixtimes the diameter of inlet line 6. FIGS. 1 and 2 also illustrate atypical positioning of conventional fluid outlet line 8, which forms nopart of the present invention.

FIGS. 3 and 4 illustrate more specifically the details of inlet line 6and distributor tank 2. inlet line 6 horizontally traverses the lowerwall of storage tank 4 and upright wall 10 of distributor tank 2,terminating within the distributor tank in a downwardly and laterallydirected delivery leg 12, preferably disposed at an angle of about 45with respect to the bottom of the tank. The mouth 14 of delivery leg 12is preferably cut diagonally, substantially parallel to the bottom ofthe distributor tank, thereby providing a more planar, multidirectionalflow of entering liquid over the bottom of the distributor tank. Themouth of delivery leg 12 is preferably positioned about 2-6 inches abovethe floor of the distributor tank.

Liquid emerging from the mouth of delivery leg 12, though somewhatflattened and redirected by impingement on the bottom of the tank, tendsto continue most strongly inwardly, in the direction indicated by arrow16 of FIG. 3, until it ultimately impinges against the distributor tankwall 10. At high flow rates, mere impingement of the liquid againstsidewall 10 may be insufficient to completely overcome the horizontalvelocity of the fluid and prevent a localized overflow having sufficientresidual horizontal velocity to disturb sediment in the storage tank. Toovercome this problem one or more baffies 18 may be positioned in thedistributor tank to divert all or a portion of the incoming liquid awayfrom its normal area of impingement against the wall of distributor tank2, thereby causing such liquid to be directed against a wider peripheralsection of the wall, and more completely damping out horizontal liquidflow by translation to a gentle, nonturbulent upward flow. In themodification illustrated, two baffies 18 are shown positioned at anangle of about 45 with respect to the main flow direction of enteringfluid, and spaced apart from each other sufficiently to provide anapical aperture through which about one-third of the entering liquidwill flow in the direction indicated by arrow 16, the otherapproximately twothirds being diverted outwardly as indicated by arrows20 and 22. Obviously, many different baffle arrangements could be usedto accomplish the same essential purpose. In some cases, as where fluidis delivered to the distributor tank at a relatively low volume rate, nobaffles at all will be required.

After being laterally redirected toward the sidewalls of distributortank 2 as described, incoming liquid then flows gently and more or lessevenly upwardly through perforatedcover plate 24, consisting of acircular metal plate containing perforations 26 distributed in anydesired pattern over at least a substantial portion of its area so as toprovide a gentle, even, upward flow of fluid from the distributor tank.As a general rule the diameter of the individual perforations 26 shouldnot exceed the radius of inlet line 6, and the total area ofperforations 26 should not be greater than about 40 percent, andpreferably should be about 25 percent, of the total area of cover plate24. If the individual perforations are too large in relation to thevolume rate of entering fluid, or if their total area is excessive inrelation to the area of the top 24, some liquid may emerge from thedistributor tank with sufficient ILLUSTRATIVE DIMENSIONS, INCHESDiameter of Inlet Line Diameter of Distributor Tank Height ofDistributor Tank 36 Diameter of Top Perforations 2 Spacing of TopPerforations 3.5

(Center-to-Center) Cover plate 24 is preferably removably affixed todistributor tank sidewalls 10, as by means of bolts, clamps or the likein order to facilitate inspection or cleaning of the interior. Bafflesl8 and sidewalls 10 are preferably affixed to the bottom of tank 4 byweldments, although removable attachments such as flanges and bolts arealso contemplated.

Although for purposes of this invention, the distributor tank sidewalls10 must be substantially imperforate, it is desirable to provide meansfor draining the distributor tank when storage tank 4 is to be drained,as for cleaning or other purposes. Such a drain means is illustrated inFIG. 4 in the form of one or more small drain ports 28 located at thebottom of the sidewall, preferably in a section thereof remote from themajor areas of impingement of incoming liquid against sidewalls 10. Inthe modification illustrated, two such drain ports are contemplated,each about 1 inch by 2 inches in size.

The foregoing description of a specific distributor tank arrangement isnot intended to be limiting in scope; obviously many modified versionscould achieve the same essential results. instead of a cylindricaldistributor tank, many other shapes may be utilized such as octagonal oreven rectangular shapes, preferably with modified baffling arrangementstailored to the shape of the tank. In one modification a section of thestorage tank wall may also form part of the wall of the distributortank. In another modification, the floor of the distributor tank may besunk a few inches below the floor of the storage tank, with the mouth 14of delivery leg 12 being positioned below the fioor of the storage tank,whereby inlet line 6 can also serve as a suction line terminating in asump for draining the entire storage tank and distributor tank. Thoseskilled in the art will readily understand that many such modificationsmay be made without departing from the true scope of the invention,which is intended to be defined by the following claims:

We claim:

1. A storage tank construction for liquids comprising in combination:

I. a relatively large outer storage tank;

2. a relatively small inlet distributor tank positioned on the floor ofsaid storage tank, and having a cover plate supported on substantiallycontinuous enclosing sidewalls,

said cover plate having multiple, unobstructedperforatrons distributedover at least a substantial portion of its area providing unobstructedpassageways from the interior of said distributor tank to the interiorof said outer storage tank;

3. a liquid inlet line communicating from the exterior of said outerstorage tank to the interior of said distributor tank and terminatingtherein in liquid delivery relationship against and a short distanceabove the bottom of said distributor tank; said distributor tank andinlet line being cooperatively adapted to provide a gentle, continuousupward fiow liquid into said outer storage tank through the perforationsin said cover plate.

2. A tank construction as defined in claim 1 wherein the sidewalls ofsaid distributor tank are imperforate save for one or more small drainports located adjacent the floor thereof and a port for said liquidinlet line.

3. A tank construction as defined in claim 1 including in combinationtherewith one or more baffles positioned within said distributor tankand adapted to redirect at least some of the liquid flow from said inletline away from its normal area of impingement against the walls of saiddistributor tank, thereby providing a more even areal upward flowthrough said multiperforate cover plate.

4. A tank construction as defined in claim 1 wherein said inlet lineterminates within said distributor tank in a downwardly and laterallydirected delivery leg, the mouth of which is cut diagonallysubstantially parallel to and a short distance above the bottom of saiddistributor tank to thereby provide a more planar, multidirectional flowof entering liquid over the bottom of said distributor tank.

5. A tank construction as defined in claim 1 wherein the total area ofperforations in said multiperforate cover plate is less than about 40percent of the area of said cover plate, but at least equal to an areatwice the cross-sectional area of said inlet line.

6. A storage tank construction for liquids comprising in combination:

1. a relatively large cylindrical storage tank;

2. a relatively small, cylindrical inlet distributor tank positioned onthe floor and near a sidewall of said storage tank, said distributortank having a substantially uniformly perforated cover plate and adiameter less than about one-tenth of the diameter of said storage tank,the total area of perforations in said cover plate being less than about40 percent of the cover plate area;

3. a liquid inlet line horizontally traversing a sidewall of saiddistributor tank and terminating therein in a downwardly and laterallydirected delivery leg, the mouth of which is cut diagonallysubstantially parallel to and a short distance above the bottom of saiddistributor tank, to thereby provide a more planar, multidirectionalflow of entering liquid over the bottom of said distributor tank; and

4. one or more baffles positioned on the floor of said distributor tankdiagonally to the principal direction of liquid flow from said deliveryleg to thereby redirect at least some of said liquid flow away from itsnormal area of impingement against the walls of said distributor tank,thereby providing a more even, areal upward flow of liquid through saidperforated cover plate.

7. A tank construction as defined in claim 6 wherein the total area ofperforations in said cover plate is at least about two times thecross-sectional area of said inlet line.

8. A tank construction as defined in claim 6 wherein the sidewalls ofsaid distributor tank are imperforate save for one or more small drainports located adjacent the floor thereof and a port for said liquidinlet line.

1. A storage tank construction for liquids comprising in combination:
 1. a relatively large outer storage tank;
 2. a relatively small inlet distributor tank positioned on the floor of said storage tank, and having a cover plate supported on substantially continuous enclosing sidewalls, said cover plate having multiple, unobstructed perforations distributed over at least a substantial portion of its area providing unobstructed passageways from the interior of said distributor tank to the interior of said outer storage tank;
 3. a liquid inlet line communicating from the exterior of said outer storage tank to the interior of said distributor tank and terminating therein in liquid delivery relationship against and a short distance above the bottom of said distributor tank; said distributor tank and inlet line being cooperatively adapted to provide a gentle, continuous upward flow liquid into said outer storage tank through the perforations in said cover plate.
 2. A tank construction as defined in claim 1 wherein the sidewalls of said distributor tank are imperforate save for one or more small drain ports located adjacent the floor thereof and a port for said liquid inlet line.
 2. a relatively small inlet distributor tank positioned on the floor of said storage tank, and having a cover plate supported on substantially continuous enclosing sidewalls, said cover plate having multiple, unobstructed perforations distributed over at least a substantial portion of its area providing unobstructed passageways from the interior of said distributor tank to the interior of said outer storage tank;
 2. a relatively small, cylindrical inlet distributor tank positioned on the floor and near a sidewall of said storage tank, said distributor tank having a substantially uNiformly perforated cover plate and a diameter less than about one-tenth of the diameter of said storage tank, the total area of perforations in said cover plate being less than about 40 percent of the cover plate area;
 3. a liquid inlet line horizontally traversing a sidewall of said distributor tank and terminating therein in a downwardly and laterally directed delivery leg, the mouth of which is cut diagonally substantially parallel to and a short distance above the bottom of said distributor tank, to thereby provide a more planar, multidirectional flow of entering liquid over the bottom of said distributor tank; and
 3. a liquid inlet line communicating from the exterior of said outer storage tank to the interior of said distributor tank and terminating therein in liquid delivery relationship against and a short distance above the bottom of said distributor tank; said distributor tank and inlet line being cooperatively adapted to provide a gentle, continuous upward flow liquid into said outer storage tank through the perforations in said cover plate.
 3. A tank construction as defined in claim 1 including in combination therewith one or more baffles positioned within said distributor tank and adapted to redirect at least some of the liquid flow from said inlet line away from its normal area of impingement against the walls of said distributor tank, thereby providing a more even areal upward flow through said multiperforate cover plate.
 4. A tank construction as defined in claim 1 wherein said inlet line terminates within said distributor tank in a downwardly and laterally directed delivery leg, the mouth of which is cut diagonally substantially parallel to and a short distance above the bottom of said distributor tank to thereby provide a more planar, multidirectional flow of entering liquid over the bottom of said distributor tank.
 4. one or more baffles positioned on the floor of said distributor tank diagonally to the principal direction of liquid flow from said delivery leg to thereby redirect at least some of said liquid flow away from its normal area of impingement against the walls of said distributor tank, thereby providing a more even, areal upward flow of liquid through said perforated cover plate.
 5. A tank construction as defined in claim 1 wherein the total area of perforations in said multiperforate cover plate is less than about 40 percent of the area of said cover plate, but at least equal to an area twice the cross-sectional area of said inlet line.
 6. A storage tank construction for liquids comprising in combination:
 7. A tank construction as defined in claim 6 wherein the total area of perforations in said cover plate is at least about two times the cross-sectional area of said inlet line.
 8. A tank construction as defined in claim 6 wherein the sidewalls of said distributor tank are imperforate save for one or more small drain ports located adjacent the floor thereof and a port for said liquid inlet line. 